The present disclosure relates to person support surfaces, such as air mattresses. More particularly, the present disclosure relates to control systems for person support surfaces.
Mattresses that turn or rotate a person by some amount from side to side are known. These mattresses are oftentimes found in healthcare facilities to support patients. Some of these mattresses have what is referred to as a turn assist function in which the patient is turned, on a one-time basis, toward their left side or toward their right side for a period of time and then returned back to a flat or supine position. Some mattresses have a lateral rotation function in which a patient is repeatedly turned from side to side in a cyclical manner once the lateral rotation function is started. This is sometimes referred to as lateral rotation therapy. The mattresses having one or both of these functions typically include a number of air bladders and an air source, such a pump, compressor, or blower, that inflates the bladders of the air mattress to achieve the various functions. Some mattresses have one set of bladders that is inflated to provide general support to the person and another set of bladders that is normally inflated, or normally deflated, depending upon the particular air mattress design, to provide the lateral rotation and/or turn assist function(s) of the mattress.
Mattresses that have microclimate control, such as a low air loss feature, are also known. Some mattresses with microclimate control or low air loss have a thin envelope or layer above the rest of the mattress components and air is circulated through this layer to pull moisture away from the person's skin. The circulating air is then expelled to ambient via passages or perforations at the sides, ends and/or underside of the layer. Other types of mattresses with a low air loss feature may have small perforations on the upper surface so that air is expelled directly toward the patient to cool the patient and/or to remove moisture from the patient via direct air impingement. In either of these types of low air loss mattresses some sort of an air source remains in an operating or “on” state to provide a generally constant stream of air to the low air loss layer. Low air loss mattresses comprised of a number of laterally extending individual air sacs that are thicker than a thin upper layer are also known and tend to be of the types that have perforations on or near their upper surfaces through which air is expelled directly toward the person supported by the mattress. Another type of low air loss mattress is one that includes a perforated hose or tube in the interior of a mattress coverlet but outside a set of person support bladders contained within the coverlet. Air is expelled from the perforated hose or tube within the interior of the coverlet, circulates through the coverlet to draw moisture from the patient through the coverlet, and then is expelled out of the interior of the coverlet through one or more passages, such as holes present between teeth of a plastic zipper, for example, or through discrete perforations provided in the coverlet.